The benchmark JSE Top40 index advanced 0.01percent to 47436.82 points, and the broader all share index declined 0.02percent to 54052 points.
Lonmin lost the most ground, falling 11.56percent to R17.91, after reporting a drop in half-year production and higher costs.
Lonmin, which has all its mines in South Africa, reported a loss per share of 64.4c against 1.8c, while unit costs were higher driven by the weak mining performance.
“Longer term, we continue to argue that the company faces significant structural head winds,” Citi analyst, Johann Steyn, said in note, adding that Lonmin was its least preferred South Africa platinum stock.
Aspen Pharmacare slid 3.6percent to R275.31 after EU antitrust regulators said it would investigate whether the drugmaker was charging excessive prices for five key cancer drugs.
The bourse’s biggest gainer was Barloworld, which is southern Africa’s largest dealer of Caterpillar CAT.N mining trucks. Barloworld shares gained 5.09percent to end the session at R119.99 after the firm reported a 9percent half-year profit rise.